Cutting tool



March' 1, 1949.

Filed May '7, 19 45 L. A. SMITH 2,463,063 CUTTING TOOL I Q 2 Sheets-Sheet '1 March 1, 1949. 2,463,063 CUTTING TOOL Filed May 7, 1945 2 Sheets-Sheet 2 hrv/a/ {ammo/714. 5 77/71? Patented Mar. 1, 1949 UNITED S'lATES PATENT OFF-16E CUTTING TOOL Lawson AcSmith, Los Angcles, Calif., assignor to Robert H. Clark, LosAngeles, Calif.

Application May '7, 1943,.Serial Non 185,984

6 Claims. 1

Thisinvention has to do with a cutting toolnnd has particular reference to a tool operable to cut roundlopeningsin various materials A general object'of the invention, is to provide a, simple, practical, efiicient and smooth open-siting tool of this character.

It is generally recognizedthat inthe operation of a cutting tool and particularly a metal. cutting tool there is a marked tendency for the toolor the work, or both, to vibrate .or chatter. This tendency varies with working conditions. such as the material being cut, the speed of cutting; etc. In the large majority of cutting, operations this tendency to chatter is present and results inirregularities in. the cut surface. In some instances these irregularities are barely perceptible, while in other cases they are, readily apparent.

A cutting tool that presents a plurality of: cutting edges, one following another, otters-many advantages, such as speedof cutting, distribution of loads and strains, balanced operation, etc. However, in the pasttattempts to provide such tools have resulted in .structuresflthat vibrate-or chatter excessively,

The highly undesirable chattering of cutting devices having a number of .cutting:..edges results from the fact that the cutters following one after another, and each having a like tendency to chatter or track one in the path of another, results in a compounding or amplification of the chatter.

I have, by my present. invention, provided a cutter in which the tendency to chatter or vibrate is minimized and for all practical purposes eliminated. By my invention .Ihave eliminated the tracking action that tends to multiply or augment the chatter, and I haveestablished a cutter arrangement that operates rapidly, efficiently, and uniformly.

A'primary object of my inventioni-s to provide a cutting tool for cutting round openings-in various materials having a plurality of cutting parts or edges so related or disposed as to eliminate or minimize the tendency of the tool to chatter as it works.

A primary object of this invention is toprovide a multiple-cutter tool of the character described which makes it possible to cut holesrof various sizes in various materials, including hard, metals, with great speed and accuracy and with a minimum of wear and strain. By my present invention the power necessary for cutting an owning is minimized, time-is saved, and general. economy is eflected by minimizing the requirements for rep-air, replacement or maintenance of the cutting tool.

Ill

Another object of the inventionisto provides hole cutting tool; ofthe character referied, to involving a pilot or: cemzering,device andtana-arrangement ofcutters: whereby the strains: and pressures onthe pilot are. minimized witharesultingminimizing of friction: and wear.

It is a general object of this invent-loam provide a cutting tool suitable for-cutting amwide variety of materials, including-steel, iron and other metals, wood plastic, 6136,,Whi0hlDI-Qf6ldbl5] has three equally spaced cutters adjustable to out openings of various sizes and which act simultaneously to take their respective pertionsmf the feed 'pressure-impartedto the tool,- and which cutters are so positioned with: respect to their carrying head and have theircuttingedges so formed as to result in a smooth, steady operation of the tool.

It is another object of this invention to. provide a cutterof .thecharacter mentioned in which :2 plurality of ut ers are arranged around thecentral or principal axis of the tool so that thetorces in thetool andwork are distributed symmetrically. With thepreferredconstruction I providerthree cutters arranged with cutting, edges substantially 120- apart around the axis of the tool. Thisresults in a structure that is'balanced, aster stress and is symmetrical and balancedas tos cture.

It is another. object: of this invention towprovide a cutter of thecharacter referred tohavingsindividually adjustable cutters arranged so that the cutting parts r are: maintainedain; proper: position relative to thework in all positionsof adjustment.

A further object oi the inventioni is-to provide a cutting tool having a cutter: in which the leading point is'dressed off to prevent-excessive digging of thecutterinto thematerial being; out; The tip ofthe cutter which. tends-to biteondig into the material is, in accordance with, my invention, slightly flattened or dressed. away to develop a tendency to dragratherthan to-biteinto the work.

Another object of the invention is to". provide a cutting tool in which there is a plurality; of cutters having cutting; edgesdisposed a manner to result in a balanced,smoothteuttinggaction. The cutter of thepresent: invention; will operate to effectively cut. a wider-angeof materials withoutr'vari-ation in the dressing or shaping, of the cutting parts and byreason-oi the principles of the present invention" the cutting action is accomplished with a mini-mumof weauwith little orno vibration or chattering, Any vibrationorchattering that .may occur. is not disagreeableeor harmiuL-either to thdtool or to 'the work;

Another object of my invention is to provide a three bladed cutter in which the pressures and strains incidental to operation are distributed around the axis of rotation so that no part or portion is unduly strained and so that this tool operates efiiciently either when rigidly held in a machine or when operated by a hand or portable unit.

A further object of the invention is to provide a tool of the character described which combines the advantages of a three bladed cutter with the action obtained by giving a slight drag effect to the tips of the cutters so that rapid smooth cutting is obtained without an excessive tendency to bite or grab the work.

Another object of my invention is to provide a multiple-cutter tool with a predetermined vari ation in cutting angle between the cutters making it possible to produce the parts of the device on a production basis and have them operate perfectly when assembled; thereby eliminating the necessity of hand finishing such as requires individual skill and judgment.

This application is filed as a continuation in part of my present pending application, Serial No. 449,905, filed July 6, 1942, entitled Cutting tool, now abandoned.

The various objects and features of the present invention will be best and more fully understood from the following detailed description of typical embodiments of the invention, throughout which description I refer to the accompanying drawings, in which:

Fig. l is a side elevation of a typical, practical form of the invention. Fig. 2 is an enlarged face or end view of the tool embodying the invention, being an enlarged view taken as indicated by line 22 on Fig. l, a circle being added to indicate the path of the cutting parts, and lines being added to indicate the angles at which the forward faces of the cutters are disposed. Fig. 3 is a front or face view of one of the cutters of the tool showing it as related to the material being cut. Fig. 4 is a view similar to Fig. 3 of another cutter of the tool. Fig. 5 is a transverse sectional View taken on line 55 on Fig. 4 showing the manner in which the cutter feeds into the work and illustrating how the tip portion of the cutter is dressed to prevent a tendency to bite or lead into the work. Fig. 6 is a view similar to Fig. 5 taken on line 6-6 of Fig. 4, showing the manner in which the tool cuts along the cutting edge removed from the tip portion. Figs. '7 and 8 are views illustrating two manners in which the pilot may be applied to the body of the tool, Fig. 7 also showing a modified construction whereby the shank and body are formed of separate parts. Fig. '9is a perspective view of a modified form of cutter in which the cutter is formed of a permanent shank and a replaceable cutting tip dressed to have the desired cutting parts. Fig. 10 is a view showing a gauge applied to the tool in place of the pilot to facilitate adjustment or setting of the cutters. Fig. 11 is a view illustrating the manner in which the cutter of the present invention cuts through a curved surface, such as that of a pipe, without grabbing.

The tool provided by this invention is useful, generally, where it is desired to cut a hole or opening in a body of material. The invention can be used to cut openings in flat sheets or bodies of material or in round members such as pipes or boilers. suitable for use in operation on various materials. For instance, it may be used on various metals,

Furthermore, the invention is plastics, fibers, woods, compositions, etc. It is also significant that the invention contemplates a tool embodying a multiplicity of cutters and in its preferred form provides a tool having three cutters. It is to be understood, however, that there are phases of the invention not confined to any particular number of cutters but which may be incorporated in structures involving two or more cutters.

The tool illustrated in Figs. 1 to 6, inclusive, of the drawings, includes, generally, a head or body iii, a shank H projecting from what I will term the upper end of the body, a plurality of cutters A, B and C, means l2 whereby the cutters are applied to the body to be rigidly held thereby and to project therefrom so that their cutting portions are properly related, as will be hereinafter described, and a pilot I3 projecting from the body to be concentric with the principal or longitudinal axis of the tool and to extend ahead of the cutters so that it may enter a pilot hole provided in the work to be cut.

The body in, in accordance with the preferred form of the invention which includes three outters, is a body or block of metal, preferably steel, hexagonal in cross sectional configuration and sufliciently long to carry the parts hereinafter described and of sufficient size and length, genorally, to form a substantial or rigid base element for carrying the working parts. In a tool designed specifically for heavy work, as for instance for cutting steel or other metals, it may be desired to make the body Ii! larger or more substantial than in a case where the tool is specially designed for working on light materials where the pressures or working strains are less severe. A design and proportioning of the body suitable for general machine shop use or practice is illustrated in Fig. 1 of the drawings. The body ID has a forward or leading end 19 from which the cutters project.

The shank ll of the tool shown in Fig. 1 is formed integrally with the inner or upper end of the body Ill. The shank is designed to facilitate attachment of the tool to a machine or operating part and for this purpose it may be the usual tapered shank or stem found in machine tools. In the form of the invention illustrated in Fig. 7 the shank I l instead of being formed integrally with the body m is a separate part provided with a threaded pin 15 which is engaged in a socket I 6 provided in the upper end of the body w The cutters A, B and C are in a general way alike and each includes an elongate shank portion l! which is engaged and held by the body ll] through the means l2 and an active or working end portion the details of which will be hereinafter described,

The means l2 for fitting or applying the cutters to the body IO may, in accordance with the broader principles of the invention, be varied considerably. In the simple preferred form of the invention shown in the drawings each cutter is arranged in a channel provided for that purpose in the body I0 and a retaining device is provided for fixing the cutter rigidly to the body. Where there are three cutters A, B and C applied to a hexagonal body it is most advantageous to provide cutter-carrying channels I8 in every other surface around the body, as clearly shown in the drawings.

The several channels H] are alike in size, shape and location so that the tool is symmetrical, each channel being formed at an angle through or across a face of the body so that it carries a tool irra'man-ner toproje'ct downwardly from or beyondthe lower end surfacelfl of the body and outwardly so that its outer orcutting end portion -isasubstantial distance outwardly or radially removed from the body. The exact angle at which the cutter carrying channels are formed is not critical although it is preferred in practice to form them at an angle of about 38 relative to aplane at right angles to the longitudinal axis of' the-tool, as that results in a disposition of the cutters that-facilitatesa practicaL-effective dressing ofthe cutting-tends of the tools; as will be hereinafter described.

i Thelcutters may be formed of stock of various shapes, 'ittbei ng generally practical to employ eutterlstock that is substantiallysquare in cross section; iILWhiCh' case theichannels are made: suffici-ently' deep toreceive the cutters so they pro.- ject only slightly fromithe channels when resting on the bottoms thereof.

" The -means provided for securing the cutters inthetchannels may .varywithout departing from the presentinventionc In the caseaillustrated a flueadedsocketiilis provided in each facewhich has-awhannel 4.8., .the socket'Zllbeing located nearsthe channel. A cap screw, orthe like, .2! is threaded into thesocket and a, clamping ring 23 is carried on the cap screw and is of sufficieiit size to; overlap .or overhang the cutter. When the screw is tightened into the socket the ring 0 bears against, the, cutter and, thus frictionally hlampstit rigidly -inr place relative to the body.

The desi n.oruformation of the ctive or .cut-

ends ofthe cutters is an important phase otthepresent invention. The ut i g ends of h sereral cutters are. in a general way. alike. However, in certain important aspects they differ. I will proceed to describe first the general characteristicsaof the-cutting or active end portion of the, cutters common to all of them, and will refer tonne cutter, it being understood that the description is applicable to all.

The flank portion 25 of the cutting end recedes from what I will term the vertical leading edge 26 of the cutter. This flank surface is curved and may be formed so that it is concentric with the principal axis .of the tool when the cutter is withdrawn or set in a retracted position somewhat inward of the smallestopening to be cut by the tool.

illustrated in Figs. 5 and 6. This slope facilitates clearance of the chips and with the bottom face .28. of the cutter defines the keenness of the cutter. Thebottom face 128 is preferably dressed to extend rearwardly and slightly upward from the point where it intersects the forward face 27? so that there is bottom clearance, as illustrated in Figs. 5 and'G. The line of joinder of the forward faced] and bottomface 28 forms or defines the -,cut ting edge 30 as best illustratedqin Fig. -6 of e-theidramin si. ineetheiforward face 21 isidressed When thus formed the flank 25 has side clearance when the tool is in operation, this clear- ..ance' being clearly illustrated in Fig. 2 of the to have :a back slope and the bottom iace N ls dressed to have clearance these: faces: meet to form a cutting edge-30havingconsiderable keenness, that is, a marked: tendency to out -intd the material which may tend-to cause :the cutter to bite or dig, if care is not exercised in -feeding the cutter into thematerial.-

To minimize or eliminate the tendency ot the cutter to dig or bite into thematerial -I dressthe tip end portion St I of the=1eading=face -21taway or back so that this portion of the face-isnnore nearly perpendicula-r to the direction of travel of the cutter or is more-blunt. Bythus dressing 01f thetip of'the cut-ter it is given-something-ofa drag action-rather thana digging action. For most 1 purposes it is. only necessary tothuseblunt the extreme end-portion 3| "of the face -21; as shown in the drawings, leavingthe balanceof the cutting-edge 30 along the bottom margin ofthe face-.21 keen to be highly efficient in its cutting action.

It will be observed that the channels, being out in the faces of the body but not sufiieien-tly deep to-intersect the principal axisof the' -body, operateto carry the cutters A, Band C sothat they are at angles to. lin-esdrawn radially from the principal axis through the tips i of the cutters. This angular disposition of the cutters is indicated by-the-angle Z in Fig. 2.- It is this bodily angular disposition .of the cutters r-e'lative to radial lines which define what may :be termed the front side slope or merely the-side slope of the cutters. The combination of the sideslopeand the back slope form the actual chipangle or the -face from which thechips are dischargediafter being-parted by the cutting edge.

. By forming or .shapingsthe cutting portions of the-.severalcutters A, Band C" exactly as de.- scribed, and as illustrated in Figs. 4,5:and 6; and byxforming; the cutter carryingchannels symmetrically-in. thebody 10,: the: several cutters when adjusted to project equally from :thebodywW-ill haveqequal and like cuttingactiom Any tendency iQI'IOHQtGl-Ititfil" to chatter will; because. of thelikeiness of the sey eral cutters, be foundimallwot=-the cutters; and thus, chatteringlaction would sbetagr vated'.

y my pre ent inventionxIl maintain :the.=desirable form nd dress ofthecuttingtportiens.of the several. cu ters. but effeetra va iation: between adjacent cutteraor at =leastcbetween one. cutter and the others;, S0c-that their .acutting actionsare not exactly, alike. but rather vary; particularly with reference *tOWhfitlifiliIl so thatwchatteri g action iSzIfillztldLiZQdQli z-practlcaliyeliminatedu .In accordance-with theinwention l1 accomplish this y ry e .i.sidesslopeof:one ofitthetcllttersyso th tthe. sidewsl pe angleof thaticutterhdifiers f om the sideslope hgleqofthe othencutters. lnihraoticef a; difference or variation .of aboutfif works satisfactorily.

i In. the embodiment oflthe invention illustrated I yaw-the side slonaangle of putter: A .so that. it is different fr m thfllhfiffillttfiirs B .and...C..1 This issaccomplished. by dressing:v the portion: 21a of the leading or. forward face 12]: :of cutter A: back, a showhin Fi .1 2, .to forman angle withwhat otherwi e w ul 'be thesidesl pe ang e: Byit-hus disposing: the portion .21 .of 1 the; forward face: of cutterALat an angle different from the: forward faces of cuttersgB and the .ciittingaedgetfle :of cutter; A, although it outs-.in t exsame path as the iotl er cutters; is-..disposed: at a; .cutting.. angle 1. dif erent from .thatqpf: the cutting-wedges :Df-ziflllifififiefi and.;@.x-and-.=thus.- will notztracklwith '7 the cutters l3 and C but will have a slightly different cutting angle and cutting action and will remove any chatter marks formed by the immediately preceding cutter and, if it should form any chatter marks, the following cutter will act to remove them.

In Figs. 1 and 2 I illustrate a pilot I 3 projecting downwardly from the bottom face or leading end 19 of the body to extend ahead of the cutters and in Fig. '7 I illustrate a typical manner in which this pilot may be related to the'body. A central or axial bore it is provided in the body extending upwardly from its lower end IS. A pilot pin extends into this bore. A transverse pin 4! is carried by the body to intersect the bore 40 and the upper end portion of the pilot pin is provided with a beveled face ii! to cooperate with the pin 4! and establish a wedging action to secure the pilot pin in place in the bore 50, In Fig. 8 I show a set screw M for holding the pilot in place. In practice a pilot drillmay be used in place of a plain pilotpin.

In Fig. 10 I illustrate a gauge pin 50 applied to thebody instead of the pilot pin, the gauge pin being for the purpose of facilitating arrangement of the cutters symmetrically preliminary to a cutting operation. The lower or projecting portion of the gauge pin 50 is flattened to present a face which intersects the principal axis of the tool. An operator can set the cutters by placing a measure or scale against the face 5i so that it projects radially to the cutter to be set, the set of the cutter being determined from the scale thus located. When the several cutters are thus set in like manner the gauge pin may be removed and the pilot pin inserted. It is possible, of course, to set the cutter by means of suitable gauges or by measuring from a pilot pin such as is shown in Fig. 1.

In operation the tool is applied to a drill press, hand power unit, or other device suitable for driving it. In most cases a pilot opening is first formed in the work and then the tool is fed to the Work so that the pilot pin l3 enters the pilot opening in the work, thus centering the tool relative to the work. As the tool is fed against the work the cutting points of the several cutters simultaneously engage the surface of the work, assuming of course that the work surface is fiat, and as the tool is rotated the several cutters take a cut into the surface removing a chip, as illustrated in Figs. 5 and 6. The cutting operation proceeds as the tool is fed against the Work. The symmetrical arrangement of the several cutters results in a balanced distribution of the strain and load, whereas the variation between the cutters hereinabove pointed out results in a checking or elimination of chatter that would otherwise develop. By thus having eliminated the tendency to chatter it is possible to feed the cutter faster than would be otherwise practical, and the tool is efiicient and practical in operating on materials and under conditions that would be otherwise impossible or impractical.

It will be apparent that by eliminating or minimizing this tendency of the tool to bite or grab it is possible to use the tool in light machines or with portable power units and do satisfactory work. It is all but impossible to handle a tool of this type with a portable power unit unless it includes the features I have provided.

By providing three cutters I have provided a tool that is highly efficient on'flat work and which also works effectively on irregular or curved work .such as pipes. To bore a hole in the side wall of a pipe a two-bladed cutter is highly impractical. As such a tool revolves and is fed toward the pipe the two cutters strike and cut simultaneously and then are both free or clear of the work, resulting in irregular action that is to be avoided if possible. By providing three cutters the Work is engaged so that except at the start of the out there is always atleast one cutter at the work, thus checking any tendency for the tool to race and distributing the cutting load so that the tool operates effectively. An important feature of the invention is the fact that the cutting edges of the cutters extend a substantial distance inward and also diagonally upward, as clearly shown in Figs. 3, 4 and 11, from the outermost ends or tips of the cutters. This gives the cutters supporting engagement with the work after the points have cut through the work, and prevents the cutters from grabbing in the manner common to ordinary tools provided for this type of work.

In Fig. 9 I illustrate a form of the invention in which I provide a sectional cutter. In this form of the invention each cutter includes a shank I? provided at its outer end portion with a socket ll which carries a cutting tip ll", the tip being secured in the socket by a set screw li The projecting portion I! of the tip |l may be dressed or finished in the manner hereinabove described so that it has the desired cutting action, clearance, etc.

Having described only typical preferred forms and applications of my invention, I do not wish to be limited or restricted to the specific details herein set forth, but wish to reserve to myself any variations or modifications that may appear to those skilled in the art or fall within the scope of the following claims.

Having described my invention, I claim:

1. A tool of the character described including, a body having a shank, and a multiplicity of cutters carried by the shank to equally project forward and laterally outward from the body, the outer ends of the cutters being dressed to have cutting edges cutting in the samepath but at difierent angles relative to lines radial of the tool.

2. A tool of the character described including, a body having a shank, and a multiplicity of cutters carried by the body to equally project forward and outward from the body, the outer ends of the cutters being dressed to have cutting edges with diiierent side slope angles but to cut in the same path.

3. A tool of'the character described-including, a body having a shank and having three circumferentially spaced channels formed in it at equal angles to a plane at right angles to the principal axis of the tool, a cutter carried in each channel, and means securing the cutters in the channels so they project equally from the body, the outer ends of the cutters being located substantially apart around the principal axis of the tool and being dressed so each cutter has a cutting edge, the cutters being related so their cutting edges operate in the same path, the cutting edge of one cutter being disposed at an angle substantially 6 different from that of the edges of the other cutters to effect smooth operation of the tool.

4. A tool of the character described including, a body having a shank, and a multiplicity of cutters carried by the shank to equally project forward and laterally outward from the body, the outer ends of'the cutters being dressed to have cutting edges cutting in the same path but at difierent side slope angles, the tip portions of the cutters at the outermost ends of the cutting edges being dressed back to have a drag action.

5. A three-blade cutter comprising a head, three; elongated cutter bars mounted on a projectin'g angle outwardly and downwardly from equidistantly spaced points on said head, said cutter; bars having cutting edges formed on the ends-for the bars below the body and laterally outward thereof and set for co-planar contact with'l'the work for simultaneously cutting a hole in, at least one of the cutting edges of said cutter bars having an angle of contact with the"1work at variance from the angle of contact of the. cutting edges of the other cutting bars, means for adjustably holding each of said cutter b r}: on said head entirely independent of the other cutter bars, and a central pilot projecting downwardly from the body.

'6. A cutter of the character described including, a body hexagonal in cross sectional configuration, a shank projecting upwardly from the body, a. central socket entering the body from its lower end, a pilot carried by the socket to project from the lower end of the body, alternate side faces oflthe body being provided with channels pitched to be angularly disposed relative to a plane normalto the vertical axis of the tool, a cutter slidably carried in each channel to project outwardly and downwardly below the body, individual clamp means for setting the cutters in the chan nels, the outer ends of .the cutters being curved on radii less than that of the smallest opening to be cut by the tool to form curved flanks for the cutting parts of the cutters, the lower face of each cutter adjacent the outer end of the cutter, being pitched to provide bottom clearance during 10 operation, the forward face of each cutter adjacent its outer end being pitched to have back slope, the forward tip 01 each cutter being: cut away to have a drag action, the balance of the cutting edge of each cutter formed where the forward face and lower face joins being keen, the angle of one of the cutting edges being different than that of the others.

LAWSON A. SMITH.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 163,503 McKay May 18, 1875 281,687 Hanscom July 24, 1883 687,724 Cadell Dec. 3, 1901 1,354,848 Schilling et al. Oct. 5, 1920 1,359,965 Claudon Nov. 23, 1920 2,057,769 Dowling et a1 Oct. 20, 1936 2,188,631 Kraus Jan. 30, 1940 2,204,855 Healey June 18, 1940 2,283,491 Daley May 19, 1942 FOREIGN PATENTS Number Country Date 1,585 Great Britain 1908 228,653 Great Britain Feb. 12, 1925 346,689 Germany Jan. 6, 1922 OTHER REFERENCES American Machinist, Mar. 31, 1921, pp. 549-550.

American Machinist, June 21, 1923, p. 921. Pub. by McGraw-Hill Pub. (30., 330 West 42nd Street, New York, N. Y. 

